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author | Andrew Waterman <andrew@sifive.com> | 2022-10-20 13:35:13 -0700 |
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committer | Andrew Waterman <andrew@sifive.com> | 2022-10-20 13:35:13 -0700 |
commit | c8665f1263baece5312c7b6291ae635123ad125d (patch) | |
tree | 9868854fc22c6958b64e4ac30ac4559dde8ba094 | |
parent | d25c67b482ffc46055d3201f38db94c1534f7602 (diff) | |
download | riscv-isa-manual-c8665f1263baece5312c7b6291ae635123ad125d.zip riscv-isa-manual-c8665f1263baece5312c7b6291ae635123ad125d.tar.gz riscv-isa-manual-c8665f1263baece5312c7b6291ae635123ad125d.tar.bz2 |
Specify which instructions are affected by Zamzam
-rw-r--r-- | src/zam.tex | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/zam.tex b/src/zam.tex index 085ab51..16818f2 100644 --- a/src/zam.tex +++ b/src/zam.tex @@ -5,7 +5,11 @@ accepted as standard by RISC-V International.} This chapter defines the ``Zam'' extension, which standardizes atomicity -guarantees for misaligned memory accesses. +guarantees for certain misaligned memory accesses. + +\begin{commentary} +The Zam extension does not alter the specification of aligned memory accesses. +\end{commentary} The Zam extension defines the concept of ``misaligned atomicity granule'' (MAG), an aligned power-of-two number of bytes within which a misaligned @@ -31,6 +35,6 @@ multiple MAGs must raise an exception, whereas regular loads and stores may either raise an exception or proceed non-atomically. \end{commentary} -\begin{commentary} -The Zam extension does not alter the specification of aligned memory accesses. -\end{commentary} +The Zam extension affects only the memory-access instructions defined in the +base ISAs and the A, F, D, Q, C, Zcb, Zfh, and hypervisor extensions, and only +those memory accesses no wider than XLEN bits. |